console.log(Number());//0
console.log(Number(true));//1
console.log(Number(false));//0
console.log(Number(null));//0
console.log(Number(undefined));//NaN
console.log(Number(''));//0
console.log(Number('123'));//123
console.log(Number('123.456'));//123.456
console.log(Number('hello'));//NaN